Process and apparatus for drying vehicles

ABSTRACT

The description is of a method for drying vehicles in washing establishments in which after the washing or clear rinsing step and before the drying step water containing a wetting agent is applied to produce a substantially uniform thin water film on the vehicle, wherein the drying is achieved through infrared ray generators or by means of other heat ray generators, and the moist air is withdrawn. An apparatus for carrying out this method is also described. The thin water film guarantees a rapid evaporation of the water from the outer surface of the vehicle with reasonable energy consumption and at the same time serves as an overheating protective device for the vehicle surface.

TECHNICAL AREA

The invention concerns a method and an apparatus for drying vehicles inwashing establishments.

STATE OF THE ART

The most widely used method for drying vehicles in washingestablishments is the use of large high powered drying blowers. In thismethod the water in advance of the drying step has added to it a surfacetension chemical means which has the effect that the water pulls itselftogether into large drops which can be peeled off of the surface of thevehicle by the air current. Disadvantages are that the high powereddrying blowers have a high energy consumption, create very much noiseand are therefore not very environmentally acceptable. The large amountof noise produced by such blowers has made it such that washingestablishments equipped with such blowers are not allowed to be set upin the middle of residential areas, but only outside of such areas, forexample in industrial areas.

Indeed a method has already been made known (German Periodical"Tankstelle+Garage" Volume 11, 1969, Page 533), in which the water hasadded to it chemical means which chiefly lower the tension of the waterso that the major portion of it runs off while the remaining portion ofthe water becomes partially underlaid by the chemical means toaccelerate the drying and to avoid spots. In this method air drying isinvolved with out the use of blowers, for the vehicles are simply set inthe open after washing and are left in the open until dry. A washingestablishment using this drying method can be set up in a residentialarea since it creates no noise, but nevertheless it does have thedisadvantage that the drying step requires too much time. This method inwhich the drying effect makes use of the surrounding air has thereforetoday been almost entirely surpassed.

British Pat. No. 1,029,004 discloses an apparatus for washing and dryingvehicles in a portal washing establishment in which heat lamps are usedfor drying the vehicles. Such an apparatus has never found an entry intopractice and has never appeared in a realizable form on the market. Thereason for this resides in the fact that with such apparatus it is notpossible to achieve such a complete drying that the vehicle after thedrying is free of drops. The removal of residual drops takes too longwith this apparatus in comparison to the time required for the drying ofvehicles in present day washing establishments wherein the vehicles aremoved with a speed of between 14 meters a minute and 18 meters a minutethrough the plant. In connection with this the upper surface of thedrops on which the infrared energy delivered by the heat lamps works istoo small for the drops to take in sufficient energy to be brought to astate of evaporation in a reasonable amount of time. A furtherdisadvantage is that the large portion of the vehicle body not coveredby the drops is struck by the infrared energy as a result of which thesurface of the vehicle body is unnecessarily overheated and is moreoverunevenly heated. Further, this known apparatus has the disadvantage thatbecause of the short building length the portal arches must work withhigh heat lamp power which not only amplifies the danger of overheatingthe vehicle surface but also leads to a corresponding waste of energy.Finally there exists as yet a prejudice against infrared drying becauseit can burn plastic parts which are increasingly being used onautomobile bodies and because it does not avoid leaving visible spotsand residues on the vehicle surface after the drying process. Moreoverthe known portal washing establishments are not made withoutsupplementary blower drying because the heat lamps are provided only inthe two vertical portions of the portal arches and the upper side of thevehicle is dried solely by means of a blower type air current.

German OS No. 19 24 094 discloses a drying plant of tunnel constructionfor washed vehicles in which the drying tunnel is provided with blowersfor circulating air and the damp air is withdrawn from the dryingtunnel, is warmed through a heat exchanger and is returned to the dryingtunnel. In the case of this plant, to avoid the disadvantage of a highlevel of sound connected with the necessary high powered blowers, anexpensive noise isolation is provided in the tunnel walls, and foroperating the heat exchanger additional energy is required, for exampleheating oil for an associated oil burner which heats the heat exchanger.This known plant is therefore costly both in its manufacture as well asin its operation.

SUMMARY OF THE INVENTION

The object of the invention is to so improve a method and apparatus fordrying vehicles in a washing plant that the drying process is madefaster, easier and more energy conserving.

This object is solved by the features given in the characterizingportion of patent claim 1 or in the characterizing portion of patentclaim 4.

In accordance with the method of the invention a vehicle during itsdrying is covered on its surface with a thin uniform water film (featurea), which serves as an overheating shield for the vehicle surface andespecially for plastic parts and guarantees a rapid evaporation of thewater, so that as a result of an adequate dose of wetting agent noresidue is visible on the vehicle surface after the drying step and thevehicle leaves the drying area entirely dry and free of drops; use ismade of infrared or other heating rays for the drying (feature b), whichin combination with the thin uniform water film takes care of the rapidevaporation of the water with reasonable energy use; and the damp air iswithdrawn (feature c) so that the advantage of direct energy contact ofthe vehicle by the infrared or other heat rays is obtained through theavoidance of a heat absorbing humid air veil and so that the drying stepis substantially accelerated. By means of the inventive apparatus asdefined in claim 5 the energy of the infrared ray generators which aredistributed over the inner walls of the tunnel, and whose current supplyis controlled by temperature sensors, is directed onto the entirevehicle surface and at the same time the amount of delivered energy islimited to an optimal value.

In the invention as set out by claims 2 to 5 the washing plant operatesin an environmentally acceptable way because the air is not blown intothe surrounding atmosphere, but instead is solely circulated andconducted back to the drying area. The circulation of the air takesplace in little time and with substantially less noise being developedin comparison to that developed by plants equipped with large highpowered blowers.

In the invention as set out by claims 3 and 6 heat is recovered in theremoval of water from the humid air which recovered heat can be used forthe heating of recovered water in the washing plant or for the heatingof the washing plant itself.

In the invention as set out by claims 7 to 13 surfactants contained inthe wetting agent insure an adhesion to the vehicle surface so that aresidue of the same remains which permits a spotless run off of thewater film.

SHORT DESCRIPTION OF THE DRAWING

The single FIGURE of the drawing shows an infrared drying apparatus.

EMBODIMENT OF THE INVENTION

The drying apparatus includes an elongated drying tunnel 1 with tunnelwalls 1a, 1b and 1c which are associated with an apparatus for supplyinga wetting agent containing water, which apparatus is shown schematicallyas an arched tube 10 with inwardly directed discharge orificesdistributed over its entire length. In place of the arrangement shownthis apparatus could also this be integrated with the clear rinsingstation of the washing establishment. The drying tunnel 1 is arranged atthe end of a customary vehicle washing establishment along the vehiclepathway as represented by the wheel guide rails 2. The tunnel walls 1a,1b, 1c are covered on their inner surfaces with infrared ray generatingdevices 3 with only the infrared ray generator in the upper left portionof the figure being shown. Also, in the tunnel walls are temperaturesensors 4 which are distributed generally uniformly in a row over thecircumference of the tunnel and which remotely sense the temperature ofthe vehicle surface. The temperature sensors 4 are connected with acontrol apparatus for controlling the current to the infrared raygenerators 3, which control apparatus is shown schematically as anelectric relay for only one of the infrared ray generators, so that whenthe temperature of the vehicle surface goes above a preset temperatureindicating that the water film has evaporated, the infrared raygenerators can be turned off as needed.

The tunnel walls 1a, 1b, and 1c contain air ducts 5. For circulating theair blowers 6 are arranged in these ducts. The air ducts have inletopenings for the air which is humidified by the drying process betweenthe infrared ray generators 3 and drying air outlet openings 7 at thetunnel entrance, by means of which the air is again delivered to thedrying area inside of the tunnel 1. In the air conducting ducts 5 themoist air which is withdrawn by the blowers 6 moves over a dryingregister 8 in which its moisture is released and to which an associatedcondensor K is connected through a conductor 9. The drying register 8can serve as a heat exchanger in a nonillustrated energy recoverycircuit in which in another place in the washing plant the water usedcan be warmed for washing or for heating.

The surfactants contained in appropriate wetting agents are non-ionogensurfactants such as ethoxylates having 3 to 10 EO per mol alkyl phenol(e.g. nonyl phenol) as well as synthetic branch-chained fatty alcohols,e.g. iso tridecyl alcohol, along or in admixture with conventionalanionic surfactants of the sulphonate and sulphate type.

The effect of obtaining a thin aqueous film suited for infrared dryingmay be improved by portions of linear fatty alcohols having a chainlength of C16-C18 amounting up to five percent at most, based on theamount of surfactant, as well as by additions of organic mono- andpolycarboxylic acids, such as formic, acetic, citric and similar acidsadjusting a Ph in the concentrate to between 1 and 6.

In keeping with the invention instead of infrared ray generators otherheat generators may be used, as for example those which work with solarenergy.

INDUSTRIAL UTILITY

Vehicle washing establishments.

I claim:
 1. A method for drying a vehicle in a washing establishmentafter a washing or clear rinsing step, said method comprising:(a) afterwashing or clear rinsing the vehicle and before drying it applying watercontaining a wetting agent to the vehicle to achieve a substantiallyuniform thin water film, (b) then drying the vehicle by means ofinfrared ray generators or by means of other heat ray generators, and(c) withdrawing the moist air produced by said drying step.
 2. A methodaccording to claim 1, further characterized by drying said withdrawnmoist air and returning it to the drying area.
 3. A method according toclaim 3, further characterized by removing heat from said withdrawnmoist air by means of a heat exchanger for energy recovery.
 4. Anapparatus for drying a vehicle in a washing establishment after awashing or clear rinsing step, said apparatus comprising: a dryingtunnel through which the vehicle is moved with at least one blower forcirculating air through said tunnel, a device at the entrance of saidtunnel for applying water containing a wetting agent to the vehicle toachieve a substantially uniform thin water film on the vehicle, infraredray generators distributed over the tunnel for applying heat to saidvehicle to dry the same, said tunnel having walls with inner surfaces,and a number of temperature sensors distributed over said inner surfacesof said tunnel walls for remotely sensing the temperature of the vehicleouter surface and for controlling the current supplied to said infraredray generator.
 5. An apparatus according to claim 4 furthercharacterized by an air drying register associated with the aircirculated by said blowers, and air ducts in said tunnel walls formingpart of the circulated air path, said ducts having dry air outletopenings at said tunnel entrance.
 6. An apparatus according to claim 4and 5 further characterized in that the air drying register is part ofan energy recovery circuit.
 7. A method according to claim 1, 2 or 3further characterized by using as said wetting agent a material havingas an ingredient at least one non-ionogen surfactant.
 8. A methodaccording to claim 7, further characterized in that the non-ionogensurfactant(s) is (are) ethoxylate(s) with 3 to 10 EO per mol alkylphenol as well as synthetic branch-chained fatty alcohol alone or inadmixture with conventional anionic surfactants of the sulphonate andsulphate type.
 9. A method according to claim 8 further characterized inthat the ethoxylate(s) contains nonyl phenol.
 10. A method according toclaim 8 further characterized in that the ethoxylate contains isotridecyl alcohol.
 11. A method according to claim 7 furthercharacterized in that up to five percent at most, based on the amount ofsurfactant, of linear fatty alcohols having a chain length of C16-C18 aswell as further additions of organic mono- and polycarboxlic acids areincluded in said wetting agent and adjust the Ph value in theconcentrate to between 1 and
 6. 12. A method according to claim 11further characterized in that said further additions are formic, aceticand/or citric acids.
 13. A method according to claim 7 furthercharacterized by said wetting agent including ingredients in the form ofa single or multiple component system which possess a caring, cleaning,protecting, polishing and/or other similar property.